Telephone-switch.



PATENTED FEB. 28, 1905.

A. W. HAMMER.

TELEPHONE SWITCH.

APPLICATION FILED JAN. 25. 1904.

A 5mm TATES Patented. February 28, 1905.,

PATEN TELEPH'DN E-SWlTGl-l.

SPECIFICATION forming part of Letters Patent No. 783,861, dated February 28, 1905.

Application filed January 25, 1904. Serial No- 190,637.

To It whom it may concern:

Be it known that l, ALBERT W. HAMMER, a citizen of the United States, residing at VVillow, in the county of Hancock and State of ludiana, have invented a new and usefulTelephone-Switch, of which the following is a specification.

This invention relates to telephone systems, and has for its object to provide an arrangement including a switch at each subscribers station, wherein when the switches of two subscribers are in position to connect them For conversation all that portion of the system with the exception of that lying between the subscribers is rendered inoperative. With this arrangement should a subscriber between two conversing subscribers cut his instrument into the line for conversation he would cut out the conversing subscriber at either side, depending upon the direction he would throw his switch. By this means it is impossible for an intermediate subscriber to cut his phone into the talking-circuit, as the instant that he cuts his instrument into the line for talking he cuts out one of the original instruments.

, Other objects and advantages of the invention will be understood from the followingdcscription.

In the drawing forming a portion of this specification there is shown a diagrammatic view showing a telephone system embodying the present invention, showing live subscribers, two alternate subscribers instruments being connected for conversation, while the outside and the middle instruments are out of scribers stations are indicated by the reference-letters A, B, C, l), and E.

The switches at all of the subscribers stations are the same, so that a description of one will sullice for them all. Upon the base 12 of each of the switches, which base is of suitable insulating material, there are mount ed five contact-plates 18, 19, 20, 21, and 22, the plates 18 and 22 being electrically connected by means of a wire 23, as illustrated, while the plates 19 and 21 are electrically connected by a wire 24:. Upon the base 12 are live binding-posts 25. 26, 27, 28, and 2t), ol which the binding-post 25 is electrically connected with the plate 18 through the medium of the wire and from which biiuling-post also leads a ground-wire 31. The binding-posts 26 are connected with the line-wire section to the let't at the stations B, C. 1), and E, while the binding-posts .28 are connected to the sections to the right at the stations A, B, (l, and D. The binding-post 526 at station A has no function, while the binding-post 28 at the station E has no function. Each of the hind; ing-posts 27 is connected directly with the line-wire 5. Each of the binding-posts 29 is connected by a wire 32 with the corresponding plate 20, and from each binding-post- 29 leads a wire 33 to the subscribers instrument, as illustrated, and lrom each subscribefis instrument there leads a grouml-wire 3 L.

Pivotally mounted at one end upon each ol the bases 12 are a series of three contact-liu' gers 35, 36, and 37, and those lingers are com nected by an insulating cross-bar 38, pivoted thereto and having a handle 39 for shifting them upon their pivots. The contact-lingers are so located and proportioned that the lin= gers 35, 36, and 37 may rest upon the plates 19, 20, and 21, respectively, or llllQGl'S 35 and be may rest upon plate 18, with linger 37 on plate 20, or linger 35 may rest on plate 20, with lingers 36 and 37 on plate 22. The [ingers 35, 36, and 37 are electrically connected, respectively, with the binriling-posts .26, .27, and 28 by means of wires, as illustrated. Normally the lingers 35, 36, and 37 are on the plates 19, 2.0, and 21, respectively.

When a subscriber wishes to call another, he operates his magneto in the usual way to give a number of rings corresponding to the subscriber wanted, the current from the magneto, one terminal of which is grounded from the telephone instrument, as illustrated, passing to bindingpost 29, thence through the wire 32 to plate 20, finger 36, and binding-post 27 to wire 5, the telephone instruments, with their signal-bells, being normally connected in multiple between the wire and the ground, as shown. Supposing that subscriber B has called subscriber D after sending in acall, subscriber B shifts thehandle 39 to the left, as illustrated, so that the fingers 35 and 36 rest upon the plate 18 and the finger 27 upon the plate 20, it being noted that the plates 18, 20, and 22 are sufiiciently wide to accommodate two contactfingers simultaneously. Subscriber D shifts his switch to the right, as illustrated. The talking-circuit between subscribers B and D is then as follows: telephone 1 1, one terminal of which is connected with the ground, wire 33, binding post 29, wire 32, plate 20, finger 37,

post 28, wire 8 to the switch of subscriber C, y

i terminal of thetelephone is connected, a pair where it passes to binding-post 26, finger 35. plate 19, wire 24:, plate 21, finger 37, post 28, wire 9, post 26 of subscriber Ds switch, finger 35, plate 20, wire 32, post 29, wire 33, to telephone 16, and thence to ground. It will be noted that the current passes through station 0 without affecting the telephone in any particular. It will be noted that the talkingcircuit includes a sectional line-wire and that the finger 35 at station B is upon plate 18, so that the line wire section 7 is grounded through the finger 35, plate 18, wire30, post 25, and wire 31, and also that the line-section 10, leading to subscriber E, is grounded at the station D through binding-post 28, finger 37, plate 22, wire 23, plate 18, wire 30, post 25, and wire 31. Therefore subscribers A and I E cannot cut into talking-circuit between subf scribers B and D. .Should the intermediate subscriber C throw his switch-fingers to the left, he will substitute his telephone for sub- 3 scriber Bs telephone and will ground the linesection 8 coming from station B in the same way that B had previously grounded the linesection 7 coming from station A. Should subscriber C throw his switch-fingers to the right, he will ground subscriber Ds instrument and put himself into communication with subscriber B. Thusit is impossible for him to hear a conversation between subscribers B and D, although it is possible for him to enter the conversation. In other words, the system is such that only two instruments can be thrown into series in a single talkingcircuit.

lVhat is claimed is- A telephone system comprising a continuous line-wire, a sectional line-wire and a plurality of subscribers stations, each comprising a switch and a telephone, one terminal of which telephone is connected with a common return, a point upon the switch with which the other of contactpoints upon the switch connected with the common return, a pair of contactpoints upon the switch mutually connected, and switch-fingers connected respectivelywith the continuous line-wire and the sections of the sectional line-wire at opposite sides of the subscriber, the switch-fingers connected with line-section being adapted to rest respectively upon any pair of alternate points and the remaining finger being adapted to rest upon a ground-point in conjunction with either of the other fingers or upon the point connected with the telephone when the other fingers are upon the mutually-connected points.

In witness whereof I hereunto subscribe my name this 18th day of January, A. D. 1904. ALBERT XV. HAMMER. Vitnesses:

F. M. HAMMER. HENRY HAMMER. 

